StringExtensions.cs

// Before:
public static class StringExtensions
{
    public static string Join(this string separator, params string[] values)
    {
        return Join(separator, values.AsEnumerable());
    }
    
    public static string Join(this string separator, IEnumerable<string> values)
    {
        return string.Join(separator, values);
    }
}

// After:
public static class StringExtensions
{
    public static string Join(this string separator, params IEnumerable<string> values)
    {
        return string.Join(separator, values);
    }
}